/Engine/Plugins/Experimental/ScreenReader/Source/ScreenReader/Public/GenericPlatform/ScreenReaderUser.h
Sets the speech volume for text to speech to speak at. The passed in value will be clamped between 0.0f and 1.0f.FScreenReaderReply::Handled()if the volume is successfully set. Else FScreenReader::Unhandled() is returned.
[FScreenReaderReply](API\Plugins\ScreenReader\GenericPlatform\FScreenReaderReply) SetSpeechVolume ( float InVolume )